SpaceX Grasshopper Launch Filmed From Drone Helicopter

garymortimer writes "SpaceX's Grasshopper flew 325 m (1066 feet) – higher than Manhattan's Chrysler Building – before smoothly landing back on the pad. For the first time in this test, Grasshopper made use of its full navigation sensor suite with the F9-R closed loop control flight algorithms to accomplish a precision landing. Most rockets are equipped with sensors to determine position, but these sensors are generally not accurate enough to accomplish the type of precision landing necessary with Grasshopper."

Comments

a few VTOVL predecessors

[Trepidity]

If you're interested in this kind of thing, there are a few videos of tests of similar vehicles from the 1990s, in both the U.S. and Japan. But they never got funding to produce production versions.

Links:

McDonnell Douglas DC-X

Japan Space Agency RVT

The DC-X still holds the record for the highest flight by a VTOVL rocket, though Space-X plans to challenge that record in a future test.

Re:a few VTOVL predecessors

[ender06]

There is a huge advantage to a VTOL rocket. Obviously the goal here is reusability, but imagine being able to land your rocket back at the very same launch pad it launched from. Do a quick inspection, refuel, launch again. Won't be that simple, but that's the idea. They are actively interested in VTOL, that's the goal of Grasshopper.

The reason this is so much more attractive than a lifting body is that you're taking a lot less extra weight with you every time. The space shuttle was extremely heavy empty, a fair chunk of launch thrust was just launching the shuttle itself, not payloads or the people. So, in short, landing legs and some extra control hardware weigh a lot less than aerobodies and control surfaces. You want to be spending your fuel and thrust on the payload, not the weight of the rocket itself.

Re: a few VTOVL predecessors

[FatLittleMonkey]

Don't forget about the landing fuel you have to tote with you along your whole trip. That is not trivial weight.

Actually it is trivial. The rocket is landing almost empty, the extra fuel to get down is vastly less than the amount to go up.

There were industry studies in the '90s and early 2000s that showed fairly conclusively that the added mass of fuel (especially as rockets are never burned dry) is about the same as all the added mass and complexity from a soft-landing parachute system. (Hard landing parachutes are lighter, but not suitable for a reusable system.) Remember, most of your mass is engines and their controllers, pumps, tanks, etc, which you have to carry anyway. And with first stages (which is what Grasshopper is), you can add more fuel without affecting your payload mass. (Reusable upper stages will eat into payload mass.)

[The extra mass required for a horizontal landing, otoh, massively outweighs the small amount extra fuel required for VTOL. They aren't even in the same universe.]

Re:Elon does it again

[Teancum]

Really? Can you name any organization that has accomplished what SpaceX has done other than people who have the motto "Waste anything but time"?

Yes, in the 1960's that motto was plastered on posters and put in giant letters inside manufacturing plants for building the Apollo rockets that went to the Moon. That was nearly the same philosophy that the Russian space program had at the same time (although admittedly a smaller budget). To date, very few organization have put anything into orbit that wasn't a national government... usually of a very large country that is a permanent member of the UN Security Council. In fact, for manned flight it is only sitting members of that exclusive club and SpaceX might be able to join that elite few very soon.

If you are suggesting that Boeing and Lockheed-Martin (or their predecessor companies) built stuff and sent it into orbit, it sure as heck wasn't on their dime nor were their engineers even the only people building those rockets.